umxSummary.MxModel: Shows a compact, publication-style, summary of a RAM model

In umx: Structural Equation Modeling and Twin Modeling in R

Shows a compact, publication-style, summary of a RAM model

Description

Report the fit of a model in a compact form suitable for a journal. It reports parameters in a markdown or html table (optionally standardized), and fit indices RMSEA (an absolute fit index, comparing the model to a perfect model) and CFI and TLI (incremental fit indices comparing model a model with the worst fit).

Usage

## S3 method for class 'MxModel'
umxSummary(
  model,
  refModels = NULL,
  std = FALSE,
  digits = 2,
  report = c("markdown", "html"),
  means = TRUE,
  residuals = TRUE,
  SE = TRUE,
  filter = c("ALL", "NS", "SIG"),
  RMSEA_CI = FALSE,
  ...,
  matrixAddresses = FALSE
)

Arguments

model	The mxModel() whose fit will be reported
refModels	Saturated models if needed for fit indices (see example below: If NULL will be computed on demand. If FALSE will not be computed.
std	If TRUE, model is standardized (Default FALSE, NULL means "don't show").
digits	How many decimal places to report (Default 2)
report	If "html", then show results in browser (default = "markdown")
means	Whether to include means in the summary (TRUE)
residuals	Whether to include residuals in the summary (TRUE)
SE	Whether to compute SEs... defaults to TRUE. In rare cases, you might need to turn off to avoid errors.
filter	whether to show significant paths (SIG) or NS paths (NS) or all paths (ALL)
RMSEA_CI	Whether to compute the CI on RMSEA (Defaults to FALSE)
...	Other parameters to control model summary
matrixAddresses	Whether to show "matrix address" columns (Default = FALSE)

Details

umxSummary alerts you when model fit is worse than accepted criterion (TLI >= .95 and RMSEA <= .06; (Hu & Bentler, 1999; Yu, 2002).

Note: For some (multi-group) models, you will need to fall back on summary()

CIs and Identification This function uses the standard errors reported by OpenMx to produce the CIs you see in umxSummary These are used to derive confidence intervals based on the formula 95%CI = estimate +/- 1.96*SE)

Sometimes SEs appear NA. This may reflect a model which is not identified (see http://davidakenny.net/cm/identify.htm). This can include empirical under-identification - for instance two factors that are essentially identical in structure. use mxCheckIdentification() to check identification.

Solutions: If there are paths estimated at or close to zero suggests that fixing one or two of these to zero may fix the standard error calculation.

If factor loadings can flip sign and provide identical fit, this creates another form of under-identification and can break confidence interval estimation. Solution: Fixing a factor loading to 1 and estimating factor variances can help here.

Value

• parameterTable returned invisibly, if estimates requested

References

• Hu, L., & Bentler, P. M. (1999). Cutoff criteria for fit indexes in covariance structure analysis: Conventional criteria versus new alternatives. Structural Equation Modeling, 6, 1-55.

• Yu, C.Y. (2002). Evaluating cutoff criteria of model fit indices for latent variable models with binary and continuous outcomes. University of California, Los Angeles, Los Angeles. Retrieved from https://www.statmodel.com/download/Yudissertation.pdf

https://tbates.github.io

See Also

• umxRAM()

Other Summary functions: umxSummaryACEcov(), umxSummaryCP(), umxSummaryGxE(), umxSummaryIP(), umxSummaryMRDoC()

Examples

## Not run: 
require(umx)
data(demoOneFactor)
manifests = names(demoOneFactor)
m1 = umxRAM("One Factor", data = demoOneFactor, type = "cov",
	umxPath("G", to = manifests),
	umxPath(var = manifests),
	umxPath(var = "G", fixedAt = 1)
)
umxSummary(m1, std = TRUE)
# output as latex
umx_set_table_format("latex")
umxSummary(m1, std = TRUE)
umx_set_table_format("markdown")
# output as raw
umxSummary(m1, std = FALSE)

# switch to a raw data model
m1 = umxRAM("One Factor", data = demoOneFactor[1:100, ],
	umxPath("G", to = manifests),
	umxPath(v.m. = manifests),
	umxPath(v1m0 = "G")
)
umxSummary(m1, std = TRUE, filter = "NS")

## End(Not run)

umx documentation built on May 29, 2024, 5:40 a.m.